window.open 窗口垂直居中

function openWin() {
  var url = '...';
  var name = '在线客服';
  var iWidth = 720;
  var iHeight = 600;
  var iTop = (window.screen.availHeight - 30 - iHeight) / 2;
  var iLeft = (window.screen.availWidth - 10 - iWidth) / 2;
  window.open(url, name, 'height=' + iHeight + ',,innerHeight=' + iHeight + ',width=' + iWidth + ',innerWidth=' + iWidth + ',top=' + iTop + ',left=' + iLeft + ',status=no,toolbar=no,menubar=no,location=no,resizable=no,scrollbars=0,titlebar=no');
}